Wireless devices frequently experience loading effects as a result of various environmental factors. For instance, wireless medical devices that are intended for use in or on the human body experience different loading effects depending on, e.g., the physical attributes of the body with which the device is used, the location in or on the body, the body's environment, antenna sensitivity, and wireless signal frequency. Failure to mitigate such loading effects by properly matching antenna and transceiver impedances negatively impacts wireless device performance.
Current solutions are inadequate in various respects. Open-loop matching techniques fail to account for dynamic variations in loading effects that result from changes in the environment in which the wireless devices operate. Moreover, traditional closed-loop matching techniques require the use of expensive components that occupy valuable space (e.g., directional couplers for measuring antenna impedance values), which makes such techniques particularly unsuitable for use in diminutive wireless medical devices.